I can pull the fuel tank, blow out the lines and replace the fuel filters, but I'm not sure about pulling the injectors. Is that a big job?
If you have to ask, then... yes.
I wasn't actually suggesting you pull the injectors. I wouldn't even recommended it if you don't have your WSM that details the proper procedures/tightening torques, the proper tools, and some experience or at least knowledge of how to work on a diesel injection system without contaminating it or causing yourself worse problems. Typically anytime the injectors are pulled, the heat shield/gaskets have to be replaced (and should), which is not obvious to Average Joe. So maybe it's a job for Above-Average Joe.
Let's say you pull the injectors... then what? Unless you happen to have an injector pressure tester sitting around, not much, which means you'd want to take them to the dealer. The reason for pulling them would be to disassemble/clean the nozzles (probably fouled), inspect for scuffing or other issues, replace any parts needed, and test them. Otherwise, they're an unknown quantity.
Having said that, is it completely necessary? Perhaps not. It's proper procedure/what
should be done, and it also provides an opportunity to completely purge the pump, injector pipes, and injectors before causing further issues, but you might get away without doing it.
The other guys seem to be saying don't worry about it, so do the best you can to clean everything out and go for it. :thumbsup:
P.S. - there's also been some other good advice in this thread w.r.t. an oil change & fuel additives. You can find Power Service at WallyWorld.